Explosion welding, sometimes referred to as explosion bonding, is a process of bonding at least one metallic layer (a cladding layer) to at least one more metallic layer (a base layer). Explosion welding can cause metallurgical bonds to form between similar metallic materials as well as between dissimilar metallic materials.
An explosion welding process has been used to metallurgically bond a cladding layer to a base layer that is flat or substantially flat. The cladding layer and the flat or substantially flat base layer are first prepared for explosion welding. The cladding layer has a bonding surface that is prepared by polishing or grinding the cladding bonding surface to achieve a substantially uniform finish. The base layer has a bonding surface that is prepared for explosion welding by polishing or grinding the base bonding surface to achieve a substantially uniform finish.
The cladding layer is positioned to be substantially parallel to the flat or substantially flat base layer, spaced apart from the base layer at a predetermined standoff distance using one or more spacer mechanisms. An explosive composition is applied to at least a portion of an outer surface of the cladding layer that is opposite the cladding bonding layer. An explosive containment mechanism may be applied to the outer surface of the cladding layer. If applied, the explosive containment mechanism surrounds an explosion region on the outer surface of the cladding layer.
A detonation system is functionally connected with the explosive composition. Upon ignition or initiation of the explosive composition, an explosion travels along at a detonation rate through the explosion region, consuming the explosive composition. As the explosion travels, metallic material comprising the cladding layer collides at an angle with the base layer, resulting in an impact. The impact occurs at high pressure, and causes spalling of the cladding bonding surface and the base bonding surface. Particles created from spalling are ejected away in a jet created by the high pressure, as are surface contaminants on the cladding bonding surface and the base bonding surface.
In existing explosion welding systems, the flatness and the uniformity of the surfaces of the cladding layer and the base layer help make the chemical and physical results of the explosion predictable and manageable, despite the heat and the speed of the explosion.
Although there is much heat generated using an explosion welding process, little heat transfer occurs from the cladding layer to the base layer. The explosion welding process results in a metal-to-metal bond between the metallic material comprising the cladding layer and the metallic material comprising the base layer with little or no melting or diffusion.